This invention relates to a metal golf club in which a shell of a head body is cast of metal.
Recently, in view of the stability of quality, the ease of supply of materials and so on, metal golf clubs in which a shell of a head body is cast of metal such as stainless steel, titanium and an aluminum alloy, have been extensively used as so-called "wood clubs" instead of golf clubs made of natural wood such as persimmon and cherry.
Among a set of golf clubs, the wood clubs are used to hit a golf ball the hardest to get a long flying distance, and therefore if the strength of joint between a head body and a shaft is low, there is a possibility that the head body may be separated from the shaft by an impact produced when hitting the ball, thus resulting in the damaged golf club.
Therefore, there has been proposed a golf club 9 (FIG. 4) as disclosed in Japanese Utility Model Examined Publication No. 63-17490 in which cylindrical shaft support portions 3 and 5 are formed integrally respectively at a top portion 1a and a sole portion 1b of a head body 1 at the heel side thereof. There has been proposed another golf club 19 (FIG. 5) as disclosed in Japanese Patent Unexamined Publication No. 5-96031 in which a hosel insertion portion 13 extends obliquely generally vertically through a head body 11 from a top portion 11a to a sole portion 11b of the head body 11 at the heel side thereof, and a shaft 17 is inserted into the hosel insertion portion 13 through a hosel 15 of a fiber-reinforced plastics material.
However, generally, a metal golf club of this type having a metal-cast shell on a head body, gives a ball-hitting feel that is harder than that of a golf club made of persimmon or cherry, and even in the conventional golf club shown in FIG. 4, since the shaft 7 is in direct contact with the head body 1 through the two support portions 3 and 5, vibration produced when hitting the ball is transmitted directly to the shaft 7, so that a soft ball-hitting feel can not be obtained, and besides there is a fear that this vibration may adversely affect the elbow of the player.
On the other hand, in the conventional golf club shown in FIG. 5, the shaft 17 is inserted into the head body 11 through the hosel 15 of a fiber-reinforced plastics material; however, since the peripheral wall of the hosel insertion portion 13 integral with the head body 11 is provided around the entire periphery of that portion of the shaft 17 disposed in the head body 11, hard vibration, produced when hitting the ball, is transmitted from the whole of the hosel insertion portion 13 to the shaft 17, thus causing a disadvantage that a soft ball-hitting feel can not still be obtained.